1. Field of the Invention
The present invention relates to systems and methods for protecting vehicle occupants from injury. More specifically, the present invention relates to a deflection hood that enhances the inflation profile of an airbag cushion.
2. Description of Related Art
The inclusion of inflatable safety restraint devices, or airbags, is now a legal requirement for many new vehicles. Airbags are typically installed in the steering wheel and in the dashboard on the passenger side of a car. Additionally, airbags may be installed to inflate beside the passenger to provide side impact protection, in front of the knees to protect the knees from impact, or at other strategic locations.
In the event of an accident, a sensor system within the vehicle senses an impact situation and triggers the ignition of an inflator. Inflation gases from the inflator fill the airbag cushions, which immediately inflate to protect the driver and/or passengers from impact against the interior surfaces of the vehicle. During normal vehicle operation, airbags are typically stowed behind covers to protect them from tampering and provide a more attractive interior facade for the vehicle.
Often, airbags are designed to protect a vehicle occupant disposed at a certain projected position. However, it has been noted that many vehicle occupants are out-of-position (“OOP”) at the time a collision occurs. Hence, airbags may advantageously be designed to provide protection for an occupant disposed out of the typical impact position. In the case of passenger side frontal impact airbags, a somewhat larger cushion may be used to protect the passenger. The cushion may extend nearly from the roof to the occupant's lap, and may also have a sizable lateral dimension to provide impact protection in a variety of occupant positions.
Passenger side frontal impact airbags are often installed in the instrument panel of the vehicle. Often, such airbags are installed on an upper surface of the instrument panel. The inflator is installed within the panel and is disposed such that inflation gas flows upward to cause the cushion to expand upward. Consequently, the cushion tends to inflate toward the projected position of the occupant's head. The remainder of the cushion may subsequently fill with inflation gas to cushion the occupant's torso.
However, such inflation may not be desirable because initial contact of only the head with the cushion tends to put excessive strain on the neck. Furthermore, such inflation may provide less protection for an out-of-position occupant.
Known solutions to this problem include the use of cushion tethers, special cushion folding techniques, and internal devices such as loop diffusers. However, such solutions typically have limitations. For example, tethers tend to limit depth of the cushion toward the occupant, thereby reducing early restraint at the middle or rearward seat positions. Special cushion folding techniques are often difficult and costly to perform. Loop diffusers generally provide only limited improvement in deployment performance, and are typically incapable of providing focused gas redirection.